Philips Integrated Circuits PDIUSBH12 - Manual (Page 17)

Philips Semiconductors Product specification
PDIUSBH12 USB 2-port hub
1999 Jul 22 17
General Commands
Send Resume
Command : F6h
Data : None
Sends an upstream resume signal for 10 ms. This command is
normally issued when the device is in suspend. The RESUME
command is not followed by a data read or write.
The PDIUSBH12 automatically sends a RESUME command when
an event occurs downstream.
Read Current Frame Number
Command : F5h
Data : Read One or Two Bytes
This command is followed by one or two data reads and returns the
frame number of the last successfully received SOF. The frame
number is returned Least Significant Byte first.
7 6 5 4 3 2
X
1
X
0
LEAST SIGNIFICANT BYTE X X X X X X
7 6 5 4 3 2
X
1
X
0
MOST SIGNIFICANT BYTE X X X X X X
SV00835
Embedded Function
The USB host sees no difference between the embedded function
and a function connected to one of the downstream ports. Some of
the port commands sent by the host must be handled appropriately
by the embedded function to appear as any other downstream port.
The microcontroller maintains a series of status and status change
bits for the embedded function as described in the Get Port Status
command section. From these bits, the Status Change bit for the
embedded function is derived (i.e. the port specific Status Change
bits). This Status Change bit is then provided to the PDIUSBH12 by
the Set Status Change Bits command.
Host Requests
SetFeature PORT_RESET
Reinitialize the embedded function and set the Reset Change bit to
indicate that the reset has completed. Reset the Enable Status bit,
enable the embedded function and set its address to ‘0’ by the Set
embedded function Address / Enable command. Disable the
embedded function interrupt endpoint by the Set Endpoint Enable
command.
SetFeature PORT_ENABLE
Enable the function by the Set embedded function Address/Enable
command. Set the Enable Status bit.
SetFeature PORT_SUSPEND
Disable the function by the Set embedded function Address/Enable
command. Reset the Enable Status bit and set the Suspend Status
bit.
ClearFeature PORT_ENABLE
Disable the function by the Set embedded function Address / Enable
command. Reset the Enable Status bit.
ClearFeature PORT_SUSPEND
Enable the function by the Set embedded function Address / Enable
command. Set the Enable Status bit, reset the Suspend Status bit;
set the Resume Status Change bit to indicate that the resume has
completed.
ClearFeature any Change Indicator
Clear the corresponding status change bit.
Babbling condition
When the embedded function causes a babbling condition, the
function is automatically disabled by the PDIUSBH12. As soon as
the microcontroller detects the babbling error, it must set the Enable
Status Change bit and reset the Enable Status bit.
Remote WakeUp
There are three scenarios when a remote wakeup can occur. The
following describes the course of actions for each of the cases:
1. The device is not suspended and the embedded port is
suspended:
Enable back the function by setting the enable bit in the Set
Address/Enable register and update the following status bits in
the microcontroller program: reset the Suspend Status bit, set
the Enable Status bit and set the Suspend Status Change bit.
2. The device is suspended and the embedded port is suspended:
Send an upstream Resume using the Send Resume command,
enable back the function by setting the enable bit in the Set
Address/Enable register and update the following status bits in
the microcontroller program: reset the Suspend Status bit, set
the Enable Status bit and set the Suspend Status Change bit.
3. The device is suspended and the embedded port is enabled:
Send an upstream resume using the Send Resume command.